uint64_t->target_addr_t for stack pointers.

This might be incomplete. It's just a quick attempt to reduce some of
the difference between riscv-openocd and mainline. Other stack pointers
can be updated as I come across them.

Change-Id: Id3311b8a1bb0667f309a26d36b67093bfeb8380a
Signed-off-by: Tim Newsome <tim@sifive.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6586
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/rtos/rtos_riot_stackings.c

@@ -27,9 +27,9 @@
 /* This works for the M0 and M34 stackings as xPSR is in a fixed
  * location
  */
-static int64_t rtos_riot_cortex_m_stack_align(struct target *target,
+static target_addr_t rtos_riot_cortex_m_stack_align(struct target *target,
 	const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
-	int64_t stack_ptr)
+	target_addr_t stack_ptr)
 {
 	const int XPSR_OFFSET = 0x40;
 	return rtos_cortex_m_stack_align(target, stack_data, stacking,